questions [Archive] - Woodwork Forums

bitingmidge

31st July 2006, 12:51 PM

Clinton,
There are a mob of websites that will illustrate the answers to your questions, one of my favourites in photographic terms at least is http://www.blueheronkayaks.com/ Ross Leidy's Kayak pages.

Click on the Wee Lassie Link and you'll get a smorgasbord of information!

The following answers will do till Boatmik finds the thread!

For a Wooden Strip Canoe:
Stems (inner and outer) - following on from another thread where I asked about stems, do any canoe designs have a single 'inner stem', which is rebated to remove the need for an outer stem?
That could be done, but it would be a real pain. The reason that the inner stem construction is used is principally to give the strips something to adhere to at the pointy end. It's not a hard thing to do, just bung a bit of curved wood on the stem mould, and cut it to a vee that looks a bit like it will line through with the strips. Let the glue do the talking.

If I use the first mould board as a part of the structural reinforcing and to form part of the bouyancy chamber - does this remove any need for the structural reo that the stem provides. I'm assuming that the stem acts as structural reo?
The stem doesn't act as "reinforcing" in a stripper necessarily, just a means of holding it all together. It would be possible to cut the strips to length, clamp them together and run a fillet at the junction, but terribly difficult and time consuming.

Using the mould for a bulkhead is feasible, but would really make glassing the inside more of a chore than it already is, and unless you use something way heavier than it needs to be, would be difficult to do.

Think light.

Do designers use composite materials for the stems to do away with the need for bent and laid up strips of timber?
What do you mean by "composite materials"? I've only seen timber used except for a few kayaks which have neoprene "bumper" blocks tacked on like the rc racing boats.

Can the strip built canoes design the same as for a ply mould? Probably, but why? Stripping is not an easy, cheap or particularly efficient way of building. It's there for you if you enjoy the process, or want to produce a particular hull shape, or (as in Mik's case) (http://members.ozemail.com.au/~storerm/Balsacanoe/Balsacanoe.html) want to produce a lightweight special, but you have to know what you are doing to achieve that.

Ply canoes come in two varieties, the old style (heavy) framed boats with lots of flat sides, or the newer stitch and tape which rely on the shape of the ply to provide structural rigidity. (lapstrake can be of either parentage!)

So either build a nice stripper because you like the shape and want to produce a "collectable", or build quick, light and efficiently in ply!

Is there any point to putting in a small keel or something to give the canoe some stability?
There'd be a lot more point in buying a design that worked in the first place! If you mean long keel to give directional stability... if the design was right, you won't need it.

If you mean dropping a weight in like a sailing boat, no, get a wider boat!

I guess Toowoomba will turn into a sharpening and boat day eh?;)
Cheers,

P
:D

Clinton1

31st July 2006, 01:22 PM

Thanks 'Midge, I'll think about that a bit and see what other questions your answer raises. :)

Composite materials - I've been thinking about and playing with epoxy and cloth ala Cameron Potters home made micarta, and using epoxy and plane shavings or scrap veneer material (like Bridge City's Juara 'wood'). Been learing about other plastics as well.
I'm thinking that the stems could be moulded in, after the planking is laid, stapled/strapped to a mould and faired. By pouring the mould you really seal that end grain, + you can add reinforcement.

Keel: I was thinking about three things:
1. 2 or 3 inches of keel laid the length of the canoe for sideways "bite" (nice techo term!)
2. an offset keel so I can kneel in the canoe and paddle on one side only - keel balances the single side paddling.
3. I would like to be able to add a sail, and a canoe would be a dog of a shape for a sail??

Lapstrake - in my dodgy laymans terms, is that replacing the wood strips with wide ply strips? If so, I guess that was what I was getting at, using the strip design plans and using wide strips of ply instead of a sheet moulded in one or two pieces.

bitingmidge

31st July 2006, 01:46 PM

Thanks 'Midge, I'll think about that a bit and see what other questions your answer raises. :)
Bring 'em on! ;)

Composite materials - I've been thinking about and playing with epoxy and cloth ala Cameron Potters home made micarta, and using epoxy and plane shavings or scrap veneer material (like Bridge City's Juara 'wood'). Been learing about other plastics as well.
No. Expensive and heavy. If you want to play in plastic, build a plastic boat. No problem with that, you'll get a really light workable end result if you are clever, and could work in foam/carbon too for the wank factor!

I'm thinking that the stems could be moulded in, after the planking is laid, stapled/strapped to a mould and faired. By pouring the mould you really seal that end grain, + you can add reinforcement.

That's how kayak's get done in some cases, (refer to the above site again), but there's no need to be paranoid about the end grain. Nothing that three coats brushed on hasn't already fixed.

Keel: I was thinking about three things:
1. 2 or 3 inches of keel laid the length of the canoe for sideways "bite" (nice techo term!)
No. You'll have it going as though on rails in a straight line, but you'd have to shunt it like a train to get round any corner at all! See design comment above.

2. an offset keel so I can kneel in the canoe and paddle on one side only - keel balances the single side paddling.
No. Learn to balance. It's a canoe! Olympic canoe classes are about as light and twitchy as they come and those guys do ok without!

3. I would like to be able to add a sail, and a canoe would be a dog of a shape for a sail??
Not necessarily, poke around Mik's website if you haven't already done so, but like all things, do you want the compromise to be paddling or sailing performance?

Lapstrake - in my dodgy laymans terms, is that replacing the wood strips with wide ply strips? If so, I guess that was what I was getting at, using the strip design plans and using wide strips of ply instead of a sheet moulded in one or two pieces.
Yep, if that's what you mean, many strip plans could be used for these alternatives, from memory David Payne draws alternatives as a matter of course, and lapstrake is really an evolution of traditional clinker construction.

I'm actually considering doing a Wee Lassie like that, using my moulds built from Mac Mcarthy's book as quoted by Wild Dingo.

Note "considering" takes even more time than "starting" or heaven forbid, "finishing".

Cheers,

P

Wild Dingo

31st July 2006, 02:30 PM

First the "ghost line" I spoke of Ive actually only found on a couple of old sets of boat plans and most of them were from the board of an American designer named Al Mason (Ive attached a pic of it) this was within the final notes in reference to larger boats not canoes in that other thread of Matts Clinton so not relevent to canoes but rather building you a larger picture regarding the sheerline you spoke of and keel plank joins

http://www.imagestation.com/picture/sraid32/p07ef72a04b37c76abb1eb73a87f77865/fd43198f.jpg

Diagonals of Sorkust

http://www.imagestation.com/picture/sraid32/p0616acb48669c917b1c7d2750e230bb9/fd431990.jpg

Lines plan of Sorkust the boat that the pic comes from (as can be seen once I actually had Sorkusts blueprint plans sadly now all I have are these)

http://www.imagestation.com/picture/sraid28/p9bce5b8f2f2fc2ec42b83818a38e9088/fd690188.jpg

Sorkust was designed in 1930 and is somewhere around 25ft LOA (length over all) so definantly not a canoe although you can see a canoe in her double ender shape

Anyway midge covers most elequently most of your questions other than the ones relating to sails

In Mac McCarthys book he actually goes into a little bit regarding placement and design of sails for the wee lassie... other things you will need are leeboards a bit more work (or centreboard a bit bit more work work degree of dificulty increased) and a tiller... a sail on a canoe isnt absolutely necessary and means a bit more work but will be fun to get around if your basically lazy or want to just tottle about takin pics fishin and stuff... its just another demension to canoeing

When Rushton created his famous canoe and travelled the many miles he did he created a small sail to make life a bit easier... theres a couple that have been "camp cruisers" for many years ie: living and camping from their canoes and boats in the states and island hopping around the caribean who wrote a book which I cant friggin find anymore who also made the leeboards and sail for their canoe named Manatou (if my memory serves also had a small catamarran at one time) so its doable and not too difficult

However as Midge says you wont need a keel as such due to the reasons he gives however you will require a centreboard or leeboards... oh leeboards are attached to the sides and a centreboard is just that you cut this hole in the middle of the boat see :eek: and make a box like affair and insert a blade of ply with some small circles of lead inserted into it to hold it down this works as a keel

Cheers

Note... sorry about the confusion regarding the "ghostline" Clinton and hope I havent confused you again :o

Another note... where the blazes is Mik when you need him??? ;)

Clinton1

31st July 2006, 06:24 PM

Maybe Mik is actually working and not just gobbing off on the 'net, with brief moments of work, like us.:D

http://www.foacc.com/Disciplines/sailing.html

In the pics on the above link - The one on the left is the one I'd like, but would not be practicable. The one on the right looks really tame.
I take it the Leeboards are what is hangin off the canoe on the right of the pic in the above link?

Ok, heres a question:
Skegs and rudders are used in Kayaks, but not on Canoes. Each are subjected to the same conditions that make using a skeg/rudder a good idea on a kayak. So, why have a keel/skeg/rudder for the canoe?

Wild Dingo

31st July 2006, 07:03 PM

Yeah go on rub it in... workin?? I WISH!!! flamin bunged knee :mad:

Miks probably muckin about with some boat or other out in the shed lucky buggar :cool:

to the questions
A)

1) The one on the left is not a canoe... well okay maybe it is but I bet its a superduper light weight flyin machine the wing hes sittin on is the only way you can stear the thing!... my view? its a racin sailing scull rather than a canoe... the one on the right is a sailing canoe

2) yes theres one leeboard on either side

B) Wrong... Kayaks and canoes are similar yes but are not subjected to the same conditions... kayaks are generally slimmer sleeker longer and faster and paddled harder while canoes are designed generally for slow paddlin in quiet waters... kayaks can take hard water surf rapids etc canoes are not designed for such... so the need in a canoe for skegs keels and rudders is negated by your paddling and movin your bum in the seat which between them controls the movement of the canoe through the water

however! as Ive said before there are always exceptions to the rule Clinton... some people I know take their canoes to some pretty hairy places and through waters they really shouldnt be paddling a canoe in (ala white water) but they do and do it well... some have made tillers and rudders that go well with the sail.

Mate if at the end of the day your after something like that speed thing on the left... go source one!... if however you want to shoot the rapids of some river or do some beach paddling find a set of plans for a kayak and go to it... however if you plan on gently muckin about on still quiet waters build a canoe if you want to include some quiet sailing then make a mast and partner and get a sail and some haliyards and go to it

Each boat design has compromises... which is why it has so far taken me over 5 years to get to a point where I can say I know which one of 3 designes Im gonna build... now if I could just work out which of those three I like most Id bloody well start!... its why its often recommended you should go and try before you decide so find a canoe club or kayak club near you and ask them if theyd mind you taggin along with them also ask if someone would mind lending you one to use or rent one for a day or so...

I built whats called a 6 hour canoe (plans sent to me by a bloke in Nebraska out of woodenboat magazine) simply a ply canoe no epoxy or fibreglass just glued and screwed heavy as shyte but mate? We had a bloody ball with canoeythingy!... it was a compromise keep waiting while getting the moulds together while getting the timbers cut and bead and coved wait while they were sanded wait while... or get on the water I chose get on the water

bitingmidge

31st July 2006, 07:03 PM

Yep! Mik's just finished the PDRacer plan set ready for distribution, and then to go to market!

As for the canoes in the pic: The one on the right is a sailing boat. The one on the left may not be as tame as you imagine given the size of the sail. I suspect it is set up also as a sailing boat (note the rudder) and yes that is a lee board, lifted in this case as the boat is going downwind.

Canoes and Kayaks are fundamentally different craft, balanced differently, paddled differently. Sort of like sports car vs panel van (sorry canoe enthusiasts, I couldn't find a better analogy in a hurry!)

Not all Kayaks have rudders, but since most are designed to track well, the rudders do help them to get round those darned corners!

I'm going to leave it at that in the hope that someone really technically savvy jumps in!

cheers,

P:D

Wild Dingo

31st July 2006, 07:06 PM

Why is that? :o I mean I go to all the trouble of postin a long winded major post to explain things and along comes Midgey and in a few short sentances says exactly what I said! :eek:

man I guess the kids are right! :rolleyes: ... I must be a gasbag! :D

Clinton1

31st July 2006, 08:12 PM

Nah, both are canoes, just that one is an extreme version, what with the @22m2 sail and the sliding set, spinnakers and what not.:rolleyes:
I'd like to play with that, but they only really do one thing well and I want a bit more than scary pants racing.

Here's a bit more about them, http://www.intcanoe.org/icabout.html I think WD might find a bit of info about his "Rushton/McCarthy" ones.

Thanks for answering the questions. I'll hang off asking more for a while, and see if others want to throw their answers up for the ones I've asked so far.

Boatmik

31st July 2006, 08:57 PM

I don't know why you guys are waiting for me to turn up - you have put the fires out nicely.

A couple of loose threads I noted on the way through

Probably, but why? Stripping is not an easy, cheap or particularly efficient way of building. It's there for you if you enjoy the process, or want to produce a particular hull shape, or (as in Mik's case) (http://members.ozemail.com.au/%7Estorerm/Balsacanoe/Balsacanoe.html) want to produce a lightweight special, but you have to know what you are doing to achieve that.

So either build a nice stripper because you like the shape and want to produce a "collectable", or build quick, light and efficiently in ply!
Agreed about almost all - but the cedar strip does allow you to work towards really effective hullshapes with hollow enough ends to give a huge amount of directional stability - which was the lesson I learned from the Balsa Wee Lassie. Great for classic canoes. It is interesting to see that a lot of the modern boats derived for stripping don't have that same amount of hollow in the stems - so are a degrade from the original[/quote]

The other thing I learned is that you can cut the density of timber by half and the thickness of the glass by 5/6ths and the boat will still be strong enough for anything the water can throuw at it. You do lose some durability as far as handling on land.

Keel: I was thinking about three things:
1. 2 or 3 inches of keel laid the length of the canoe for sideways "bite" (nice techo term!)
2. an offset keel so I can kneel in the canoe and paddle on one side only - keel balances the single side paddling.
3. I would like to be able to add a sail, and a canoe would be a dog of a shape for a sail?? 1,2 Don't do it - you will ruin the canoe. The traditional designs are beautiful compromises between directional stability and manoeverability.

3 Paddling canoes can make very fast sailing boats - their only real drawback is their reluctance to change direction - OK as far as course changes and gybing but they just won't make it through a tack - just keep a paddle handy or be prepared to sail out of being in irons by sailing backward.

There are two ways of going with sailing canoes - build a more sailing oriented design or build some drop in outriggers and put a monster sail on for scorching performance. You don't need a cantreboard because the leeward outrigger will take the lateral loads. The other way is just to put a basic little rig with an integrated leeboard - see website for simple light solutions.

Skegs and rudders are used in Kayaks, but not on Canoes. Each are subjected to the same conditions that make using a skeg/rudder a good idea on a kayak. So, why have a keel/skeg/rudder for the canoe? Kayaks are open sea boats. If using them inshore like a canoe is designed to do you don't really need a rudder for either.

1) The one on the left is not a canoe... well okay maybe it is but I bet its a superduper light weight flyin machine the wing hes sittin on is the only way you can stear the thing!... my view? its a racin sailing scull rather than a canoe... the one on the right is a sailing canoe Both are sailing canoes - the one on the left is the International Canoe - derived from the same sort of craft that my Beth Canoe (my avatar) is based on but updated over 100 years into a serious sailing maching - until recently the fastest sailing monohull in the world.

But the downside is that both boats will be rotten paddlers compared to a classic stripper design. The one on the right will blow around horribly for a start and its leeboards might be JUST big enough to go upwind OK. It'll be a bit of a dog upwind.

you want to shoot the rapids of some river or do some beach paddling find a set of plans for a kayak and go to it... however if you plan on gently muckin about on still quiet waters build a canoe if you want to include some quiet sailing then make a mast and partner and get a sail and some haliyards and go to it
There have been a lot of seriously big rapids handled with canoes as well as kayaks - I doubt whether many kayaks got the chance to see rapids ever until recently - whereas canoes were the vessels that opened up the whole interior of Canada and the USA. Including many wild rivers.

Canoes and Kayaks are fundamentally different craft, balanced differently, paddled differently. Sort of like sports car vs panel van (sorry canoe enthusiasts, I couldn't find a better analogy in a hurry!) Dangerous waters Midge!!! Not a good analogy at all. Canoes are open - kayaks are decked. End of story.

The only forming factor is that a canoe cannot be as fine and as low in the ends at deck level as a kayak - the water would come aboard - but still quite possible to make very fast paddling canoes.

Most of the classic canoes have been designed to carry real loads or paddle beautifully laden light - Chestnut Prospector (my favourite two person canoe - reputed to carry 1000lbs of furs and still paddle nicely with only one person aboard.), Sairey Gamp, Wee Lassie. But there are some narrower ones more oriented to carrying light loads - much like sea kayaks and with similar speed.

MIK

bitingmidge

31st July 2006, 09:34 PM

Dangerous waters Midge!!! Not a good analogy at all. Canoes are open - kayaks are decked. End of story.
Not a good analogy at all,(I thought that at the time!) but not end of story I'm afraid.

Canoes can be decked, Kayaks can be open-decked.

Or is Beth a sailing Kayak?

;)

P

Clinton1

31st July 2006, 10:07 PM

Wild Dingo

31st July 2006, 10:44 PM

See now I thought some our comments would drag the old fella out of hibernation kickin and screamin :D

Good to see you Mik :cool:

Okay I was a bit off the cuff with the comments re the zippyzappy left hand pic :rolleyes: ... Im the slow an easy sorta bloke to me canoeings about wandering around an estuary or up a quiet creek a small hidden lake or out the back of a dam... quiet peace solitude and gentle waters! not madly rushin about screamin as your danglin you bum in the drink as you hoot along... thats not canoeing to me

oooh sigh and yes yes I knows that the PNW and Canadian wilderness was more or less opened up by the canoes of the trappers and those dopey dupres who would scream down the rapids loaded with bear fox elk moose or buffallo... I know that but hey Im the slow an easy sorta bloke to me canoeings about etc etc etc ;)

But really mate tell us how we got on standin in for you on edjoomakatin young Clinton? :D

Boatmik

1st August 2006, 04:45 AM

Thanks Michael,
I was interested to see what comments came up on the International 10m2 class... its such a pity its just a 'go fast' evolution. It'd be nice if you could compromise between the two (sail/paddle) without losing so much from each aspect. I've been telling myself that this class is 'not practicable' for a while now - still want one though!
The 10sq Metre canoes are wonderful to sail - particularly upwind and crosswind - I sailed one for an hour or so on Lake Macquarie quite a few years ago. Very sweet and viceless and terribly fast. Proves once again that if you want good handling - go for a narrow boat with a narrow stern!! (this is just me venting!)

"really effective hullshapes with hollow enough ends to give a huge amount of directional stability" - sorry mate, I'm a total beginner... can you tell me what that means (and why, if possible).
Now Mr Clinton - I need to speak some slightly harsh words to you - but my purpose it for the purposes of your education.

If you are a beginner - why are you coming up with all these ideas? I can tell you that in particular the keel idea was pretty awful.

What you need to understand is that wooden canoe technology goes back at least 300 years without counting the Indians in the equation at all (there are thousands of years of development really). And the boats were used for more serious adventures than either of us will ever undertake - people's lives depended on them - they used them day in and day out to cover real distances with real loads often in adverse conditions.

The point is that the lessons are there in the traditional boats - that it actually is pretty hard to improve their shapes for their purpose. There are a number of things that you can do to improve their construction - epoxy glass does give a nice strong boat with low maintenance which is very unlike the old boats. But the older construction methods probably would have been more at home in rapids and other nasty situations - canvas covered ribs - you can afford to break a few and the boat will still be watertight. It is also pretty easy to stitch a patch into the canvas if it is torn.

hollow enough ends to give a huge amount of directional stability
http://members.ozemail.com.au/~storerm/Balsacanoe/balsa%20stem%20detail%20a.jpg

If you look end on at any of the classic wooden canoes (my Wee Lassie here) the first foot or three of the boat at water level and below is a vertical fin. The stern is the same. The fin at either end keeps the boat tracking in a straight line even in big winds and waves. It also makes them harder to turn - but directional stability is an excellent property of a good touring boat.

This is one area (apart from their excessive weight) where fibreglass canoe designs mostly fall down badly. The people who design them don't know about the directional stability - so the first thing they do when drawing up a new design is make the forward part of the boat very full and get rid of those nice hollows - get rid of the vertical fins. Their idea is to make the boat easier to build - make it easier to get the glass into the mould. But wander around they do and they don't cut the waves like the old boats.

Before you start worrying there is little problem getting the glass into that area of a stripper canoe - there is very little problem - it is a little more fiddly than the rest of the interior - but you don't even have to do a particularly speccy job because it is inside the buoyancy tank for the bigger boats (though my Wee Lassie didn't have them.

It is a revelation paddling one of the older designs too - particularly in company with fibreglass or polyethelene boats. They have to make three paddle strokes to your two. If you match their stroke rate you pull away and end up having to stop and wait for them around the corner.

There are some nice fibreglass boats around too - particularly in Canada and the USA - not so many nice glass canadians here.

Your comment about reducing the density of the timber - is that by using a less dense timber, or by using thinner strips?
Density is the property of the timber. The balsa I used is around 12lbs a cubic foot. The cedar is normally around 23. Used 7mm vs the normal 6mm strips for cedar.

The Chestnut Prospector is the strip canoe that is in the latest Aust. Woodworker - it prompted this thread. It looks nice - 4935mm (16 foot?) long and 25-27kg.
It was made from 19 x 6 mm WRC.
Had a peer through the article at the newsagents yesterday. It goes to show just how cool these boats are. The one in the magazine wasn't the best built I have seen but it was far from the worst. And even the worst worked beautifully in the water.

The thickness of the strips is normal but you can often get the width up more towards 22 or 23mm if the timber dimensions will allow it - saves a bit of labour and a bit of material cost.

The plans and method for the prospector are in "Canoecraft" along with around 8 other plans for some extremely cool canoes.

I think the Prospector is the nicest in the book - there is nothing bad to say about it. Carries a huge load, paddles well light, paddles nicely with one or two aboard, turns nicely and has a good reputation in rapids (for those who dare). A good honest boat with a wide range of capability.

Have a look at a couple of books - find a canoe that you think will work for you - and go for it. Stick to the traditional details - build the way the book suggests and you will end up with an excellent boat. Six months after launching you won't be a novice any more.

I can promise you that.

Make a nice paddling boat and there are a couple of simple things you can do to make it a good sailor - without mucking up its paddling ability.

MIK

Clinton1

1st August 2006, 11:27 AM

But wander around they do and they don't cut the waves like the old boats.
Thats where my canoe experience is (horrible fiberglass or plastic ones), and a few kayaks.
The keel comment was made for the purpose of finding out 'why' it is not done. At the moment I'm learning (slowly) and am 'up to' skegs and rudders in kayaks.
Harsh words: I'm asking the questions as part of my learning process - don't confuse it as someone with no knowledge thinking they have a great idea that everyone else has missed.
Edumacation! I'd prefer to do it by asking questions than spending scarse $ on a canoe to find out that it was a mistake.

I've been looking at designs and reading a few books - its difficult for a complete novice to work out what might suit a need. There's a lot of designs available - from curvy strip ones to flat sided/bottom ply ones. The sellers of the plans all say that their one is really good. Confusing.

So, I've been looking at expensive sea kayaks and comparing them to available canoes, noticing that they move completely differently - and I'd like to know why.

Anyway - My take is now that some traditional canoes (and kayaks) do have a means to impart directional stability - just that it is in the design of the ends. Cool, learnt something. Thanks!

God, it would be nice if I could find some simple rules of thumb for what to look for!

Wild Dingo

1st August 2006, 02:17 PM

Edumacation! I'd prefer to do it by asking questions than spending scarse $ on a canoe to find out that it was a mistake.

And no better way has been devised and I for one as Im sure both Mik and Midge agree... ask you to continue asking!!

I've been looking at designs and reading a few books - its difficult for a complete novice to work out what might suit a need. There's a lot of designs available - from curvy strip ones to flat sided/bottom ply ones. The sellers of the plans all say that their one is really good. Confusing.

And that my friend is what boat design selection is all about... from small canoes to large sea going yachts and everything between... to confuse the looker!! and keep them in a constant state of utter confusion.

The main thing you have to work out in choosing a design (well theres a few things actually) is what you intend to use it for... if you can firmly say I will bein doin.... (this or that) then you can narrow the field and then continue defining exactly what it is you want need and use and so continue narrowing the range of designs down... eventually you will find a few that meet all your needs

but yes your right it is confusing

Anyway - My take is now that some traditional canoes (and kayaks) do have a means to impart directional stability - just that it is in the design of the ends. Cool, learnt something. Thanks!

You mean all our effort meant nothing! :eek: oooh so sad all our effort to help you and Mik gives you the one thing... oooh woe woe woe ;)

God, it would be nice if I could find some simple rules of thumb for what to look for!

The rule of thumb will be dictated by YOU... you know what you like you know what you will be capable of building you know what you want to use it for you know what you want to be able to expect of it... so mate you dictate the rules of thumb in what your looking for

The questions are needed to begin the process of defining... you also need to find someone with a canoe not a plastic thing but a good wooden one and a kayak and try them out... Im not saying this is going to be easy Im yet to find a wooden canoe to try out myself but then I know what I like when I see it and I know what I want to use a canoe for the areas I will be using it in etc... you need to settle an deside on what it is you want and then what it is you want it for that will define the rules of thumb

Keep asking Clinton! :cool:

See sometimes we (any of us) come to the forum with other things on our minds other people have impacted on us and we bring that with us and sometimes there may have been a negative event happen and we bring that and sometimes it overflows in our posts and that often means theres some skeptism in our posts... as I think you took some offence at some of what Mik says I think he has done that and its colored his reply a tad... dont mind it relax its not you its the questions the fact you knew somethings but were askin questions about it bought out what I thought was a bit of skeptical response... as I said we all do it from time to time... relax hes not shootin you down hes probably had a bit of a day... so keep askin the questions we all will keep giving you responses as we can

See I could have gotten my nose out of joint after all that Id written to help you and yet you only notice Mik... see? bit I didnt and dont cause I only try to help and Im not gonna be upset if you ignore me geez mate I get ignored by her bloody highness 9 times out of 10 so hows your ignorein me gonna hurt eh? HA! :D

Go to the library get out the books Gil Gilkinsons Mac McCarthys Ted Moores and the others and id be surprised if the answers arent in them :cool:

Clinton1

1st August 2006, 03:16 PM

Wild Dingo -
Thank you, thank you, what do you mean - i paid attention to you!!

I wasn't offended by Mik's 'hard lesson' comment- I really appreciate his time and effort.
I just didn't want anyone to think that a beginner/novice was thinking that he'd build a first canoe, and make big changes and 'kick everyones ####".

Maybe Mik sees that happen in his job - being a designer and all, I assume he'd spend a lot of time listening to people talk about what they think should be modified, instead of letting him get on with his job.
I reckon Mik might get blamed for the failure of those mods too!

In my tongue tied way I was trying to ensure that I didn't appear to be an arrogant idiot! :o :rolleyes:
Hopei didn't come across that way. :confused:

Wild Dingo

1st August 2006, 05:26 PM

Nah Clinton no worries... got questions that need askin but have some probs puttin the question into words thats normal :cool: ... well for me anyways and its why it takes me friggin ages to say what I want to say... that and tryin to make what Im tryin to say clear as possible so no doubt or confusion is out there :rolleyes:

trouble with that is it gets so friggin long winded people can get f'...ed of with me :rolleyes: and mate thats a real pain in the proverbial :o

I guess to me and most of us its best if anyones got questions about anything to simply ask them... as someone once said "only dumb question is the question thats not asked" so ask away ;)

Cheers

Boatmik

2nd August 2006, 11:08 AM

Clinton1

2nd August 2006, 11:44 AM

Ok - lets agree to blame Biting Midge (cause he hasn't put his oar in for a while) and get on with it! :rolleyes:

Mik,
can you talk to me about the difference in 'through water performance' between your ply mould canoe/boats (some of them are quite flat around the profile due to using the ply) and the same design made using strips that are shaped to a purely curved profile.

i.e. do the 'flat' ones suffer a performance loss, and is that a consequence of making the design so 'user friendly'??
OR,
Am I wrongly assuming that there is a performance differance?

Anyone notice the nice 'boaty' pun ?? :D

Edit: maybe flat is not the right word - angular??

bitingmidge

2nd August 2006, 12:04 PM

Since it's my fault! :cool: And to skip your last question:

The sellers of the plans all say that their one is really good. Confusing.

Sadly that is a big problem.

Boat "A" is sold as the best boat in the world, and is really a dog, but no-one who buys/builds one has any other experience, so all believe it to be the case. Life imitates the advertisers art. The users never seem to question how it is that Boat "B" sails past them, it's crew arrive happier, rig easier etc etc etc.

Boat "B" on the other hand, (and I think the Goat Island Skiff is one of these) is very low key, never attracts too much publicity, yet sails rings round any of the imitators making all the noise.

The best way of learning is to get out there and do it. Once you are out on the water, you will start to notice things, go for rides in other people's boats, find out what the differences are. You can learn what to look for in books, but you won't appreciate what it means till you are out there.

Be wary of anyone with fixed ideas. "Seaworthiness" to some, means building an anachronistically heavy boat with a long keel (no offense Dingo), while to others (me) it means building light, strong, fast.

I happen to enjoy being in a warm bed at the end of a long sail, while the owners of other "more seaworthy" boats are out there for another day or two enjoying their "seaworthiness." Who is right? What do you want to achieve for yourself?

Mik knows this stuff because as much as anything else he's experienced it. He has the book learning, and a very finely developed instinct as well, but mostly he can tell you what works because he's been there before.

All of the best designers are out there doing it on anything that floats, constantly experiencing other designs as a means of evaluating their own (and finding fodder for plagiarism I guess!).

The only way to learn is to do the same, don't spend forever analysing, get something to use as a starting point, realising that it is the bottom step (who knows, you may luck in and get it close to right first time!), and then evaluate from there. It's so much more fun when you can analyse something first hand, make changes and go again!

I'm not dismissing your questioning by the way, just trying to make the point that it will be easier to understand the responses when you have a little more experience as well.

Cheers,

P

Boatmik

2nd August 2006, 12:23 PM

Howdy Clinton,

Happy to oblige - just did a much longer post and dammit - it got eaten up.

Ok this is my view on strip vs ply.

If fibreglass canoes (in general - and in Australia - there is more choice overseas) were not so bloody awful to paddle and so heavy there would be little place for a ply canoe except as a fast building compromise type

The classic timber boats are pretty near perfect in terms of speed, weight, paddling and load carrying.

My Eureka canoes are an attempt to get as close to this as possible in a plywood boat coming out of 2 sheets.

http://members.ozemail.com.au/%7Estorerm/Eureka/Eurekapic1.jpg

As you can see the "fin" (normally called a hollow entry) is there and it smooths nicely into a weight bearing midsection. You can see a similar transition in this pic of my Wee Lassie

http://members.ozemail.com.au/%7Estorerm/Balsacanoe/balsa%20almost%20overhead%20a.jpg

Note how the volume of the Lassie's mid body moves upward as your eye moves out to the ends of the boat.

This can sorta be acheived in plywood, but there is not as much freedom to really get the shape that would be ideal. You can see that the Weel Lassie takes it to an extreme which just can't be acheived with ply to the same extent

There is also some drag from the chines.

BUT, BUT, BUT
At somewhere between half and a third of the weight of a fibreglass canoe and with some of the features of the classic canoes and the ease of building - then there is a place for a good ply boat.

Won't be quite up to the stripper, (people are going to be so disappointed if they Google "stripper" and get this page!) but will still cream (haha) the average glass boat.

Just to remind us all of what I am talking the attached pic below is of a pretty standard glass boat - the hullshape is just a blob. They make a great play in their advertising bumph that "has an external keel running the full length which allows it to track straight".

Sigh.

If you look at the pics of the Wee Lassie and the Eureka and compare to the glass boat below - your eyes will tell you that the performance of the Eureka will be much closer to that of the classic canoe than it will be to the glass canoe.

Eyes are really important in understanding boats!

Best Regards
MIK

Wild Dingo

2nd August 2006, 01:05 PM

Since it's my fault! :cool: And to skip your last question:

Sadly that is a big problem.

Boat "A" is sold as the best boat in the world, and is really a dog, but no-one who buys/builds one has any other experience, so all believe it to be the case. Life imitates the advertisers art. The users never seem to question how it is that Boat "B" sails past them, it's crew arrive happier, rig easier etc etc etc.

Boat "B" on the other hand, (and I think the Goat Island Skiff is one of these) is very low key, never attracts too much publicity, yet sails rings round any of the imitators making all the noise.

Im thinkin subtle midgey here... somewhere Im remebering a discourse on Wharrams... yes yes thats it a subtle play on words without bein specific!! WELL DONE midgy! point taken ;)

The best way of learning is to get out there and do it. Once you are out on the water, you will start to notice things, go for rides in other people's boats, find out what the differences are. You can learn what to look for in books, but you won't appreciate what it means till you are out there.

Were repeating ourselves mate... the twins strike! :D

Be wary of anyone with fixed ideas. "Seaworthiness" to some, means building an anachronistically heavy boat with a long keel (no offense Dingo), while to others (me) it means building light, strong, fast.

ooooh right mate no offence but with reference you mean me!! oooh mate how well ye know me! :o HOWEVER!!... while tis true I have a penchant for large boats made heavy for over the horizon sailing I must admit Ive not finished looking and some Im looking at are quite small quite light and well maybe fast depending on wind factors and such... see mate Im also presently in the processes of building (and I do use that term rather loosely considering where Im at with it) an 18ft Norse boat which should be reasonbly light strong and fast and a 16ft Weekender a ply boat which I really think has a good look about her... and Ive also bought and am waiting for the plans for Bolgers St. Valery and am presently arguing with her bloody highness who is trying to cadge her way out of our agreement :mad: for the money for Cinema from David Payne... so you see mate none of those are over 20ft all are pretty light builds and well... Im not like that!! :eek: stop pickin on me!! :( :D

Mik knows this stuff because as much as anything else he's experienced it. He has the book learning, and a very finely developed instinct as well, but mostly he can tell you what works because he's been there before.

All of the best designers are out there doing it on anything that floats, constantly experiencing other designs as a means of evaluating their own (and finding fodder for plagiarism I guess!).

Strewth mate smile when you say that!!! Plagiarism indeed!! What will Mik say??? :eek: ;)

The only way to learn is to do the same, don't spend forever analysing, get something to use as a starting point, realising that it is the bottom step (who knows, you may luck in and get it close to right first time!), and then evaluate from there. It's so much more fun when you can analyse something first hand, make changes and go again!

I'm not dismissing your questioning by the way, just trying to make the point that it will be easier to understand the responses when you have a little more experience as well.

Cheers,

P

Questioning is good... questioning is good... mantra of a 5 year questioning bloke :rolleyes:

Clinton even though Im having a bit of a lighthearted go at our midgey mate hes on the money... and one thing I know about is questioning boats trouble with it is you can become focused on the questions and become confused by the sheer plethoria of design choices available now with the internet... okay were talking canoes here and one would think theres only a few ways to build a canoe right? right but there are so many near canoe boats that people will suggest to you to have a look at and in your questioning nature you will go have a look at them actually heres a real nice one plans available from Flatducks (http://www.duckflatwoodenboats.com/mainpages/kPlans.php) youve got Iain Oughtreds McGregor Wee Rob and Beaver then theyve got CLCs plans then Bear Mountains designs and so it goes... this will lead your questioning mind further and further and further till suddenly one day you will wonder what the hell your doing thinking of building a ruddy great 40ft schooner when all you really ever wanted is a small canoe and a small trailerable fishing boat of some discription :rolleyes: dont bloody ask! :o

Question to your hearts content but Dont loose sight of what you want is all Im saying... its not hard to loose sight and in so doing loose 5 years to the questions! As has been said look around find something to try ask questions and do something

oh and mate? good luck! ;)

Boatmik

2nd August 2006, 01:08 PM

More on Eyes and Plagiarism

One other area where glass boats fall down badly is that because they are generally marketing driven - ie have to look like canoes rather than be canoes they tend to exaggerate canoe features.

They almost all have the sheerline sweeping up into a high bow.

All it does is add weight and catch the wind - giving that poor overworked keel that they tout in their ads even more to do in terms of directional stability.

When I built the Balsa Wee Lassie I noticed that when put upside down on the floor the boat would tip over onto one gunwale. That gunwale lay flat along the floor its whole length apart from some fluctuations caused by my building skills.

Since then I have always drawn my canoe sheerlines in that way. It does mean that getting the width of the boat right at different points is rather critical to the appearance of the sheerline - but it does give the boat a lovely appearance.

http://members.ozemail.com.au/%7Estorerm/Eureka/eureka2x.jpg

There may be times in the future when I depart from this scheme, but for a general use boat it seems just about perfect.

And I can't really take any credit apart from grasping the significance of what I saw with my eyes. The real work was done by J Henry Rushton before 1900.

MIK

Boatmik

2nd August 2006, 01:27 PM

plans available from Flatducks (http://www.duckflatwoodenboats.com/mainpages/kPlans.php) youve got Iain Oughtreds McGregor Wee Rob and Beaver then theyve got CLCs plans then Bear Mountains designs and so it goes...

oh and mate? good luck! ;)

There is a lot of choice out there - but the learning only really starts when you have built and have used boats - which even Dingo and Midge have done (how is that Eureka going Midge?).

One of the big problems is perfectionism - looking for the perfect boat - no such thing. Every boat is a step along the way and every boat is perfect in its own terms - so long as the designer has done a half decent job!

The basic question I always ask people when they say they want to build a boat is which is more important.
1/ The building process
2/ The use of the boat at the end.

If the buildig process is important - go strip or clinker.

If the end use is important go ply.

If going strip consider the Chestnut Prospector out of "Canoecraft" the boat has a huge reputation earned over a century.

Or if wanting a single consider the Wee Lassie - even though some of the more recent re-inventions of the Wee Lassie have a lot less hollow in the bow than the original - watch out for this type of watering down too.

Going clinker - it is hard to beat the detail of Oughtred's plans.

Ply boats - with the preceding pics you probably have enough info to start judging them on their merits - look at the pics and see how they stack up against classic canoes.

Ha - Note I just gave you pretty much the same suggestions as Dingo!!!!!!!

MIK

Clinton1

2nd August 2006, 01:29 PM

who knows, you may luck in and get it close to right first time

I'm trying to get a close to that as possible, through asking questions (and using other peoples boats). I'm getting some good answers from you all.

Mik - your post will take a while for me to digest.
I think you are saying the ply canoe is a compromise.... but a damn good one? I see the sense in making the canoe/kayak out of the minimum # of ply sheets, and for that reason alone its very attractive.
I don't suppose you could put a percentage on the performance loss between "identical design, one strip, 1 ply"

Eyes - my eyes are always drawn to the really expensive options :( :rolleyes:

Clinton1

2nd August 2006, 01:48 PM

I should add - (you blokes posted heaps I haven't read properly while I did the last reply of mine) - that due to work committments I will not be able to start building untill the beginning of 2008.
I'm committed with other things till the end of this year, then go overseas for 12 months.

My plan is -
2008 build a canoe
2008 build a kayak
(depends on $) build a Goat Island Skiff

I'm hoping that along the way someone says "that canoe/kayak looks great, how much will it cost to make me one?" to help pay for the mast/rigging/sails of the GIS.

From some research on re-sale, I think that strip might be easier to sell. I'm still deciding on that though.

Boatmik

2nd August 2006, 02:02 PM

Mik - your post will take a while for me to digest.
I think you are saying the ply canoe is a compromise.... but a damn good one? I see the sense in making the canoe/kayak out of the minimum # of ply sheets, and for that reason alone its very attractive.
I don't suppose you could put a percentage on the performance loss between "identical design, one strip, 1 ply"

Nope - not possible. I've been involved in high level yacht racing - and there is a huge time and effort spent getting this sort of information - you have to be so careful.

If you are used to fibreglass canoes then try a wooden one - speak to Midge and he can put you in touch with the Qld Wooden Boat Association (I can't quite recall which participant here is directly involved in the Qld Assoc.)

In my mind the question is quite different.

It really comes down to how much building you can be bothered doing.

If you like the building process a lot - build a stripper for the ultimate in paddling performance.

If you want a boat to use with the minimum hassle on the building side - go ply - accepting that you lose a little in outright performance but you can still have a boat with good handling qualities if it has been done right.

Either boat will be a revelation after paddling an average glass boat.

MIK

Ramps

2nd August 2006, 02:23 PM

Hi Guys
just a few things that I've observed in this thread while skulking around in the dark corners for expert in this game I'm not. I'll leave the answers to the experts and only offer opinions as a newby as that is where Clinton seems to be as well (at least in the boat side of things)

My plans to build a kayak out of Nick Shades book has been waylaid due to the selfish, egocentricity of a single seated kayak:mad: so I thought I'd get some practise in first ... by building a canoe for the two of us and the two lightweights (total weight of the girls about 45kg). First thought was to get it out as quick and cheaply as possible.

After research and lots of comments from Mik I believe that ply would be quicker but the cost of good quality ply is up there with the cost for timber for a stripper. In fact I just purchased enough timber to do a caone for just under $130 whereas quality ply would be about $250 ... yeah yeah I know then there's the diferential cost of f'glass vs varnish and we could go on but what I am getting down to was that the cost differential wasn't as great as I thought it might be so I decided to buy "Canoecraft" and build a stripper so as when it came down to building a Guillemot kayak it would look OK rather than a "first attempt" ... my main reasons for going stripper .. oh yeah apart from looks and the love of working with solid non-composite timber and ...

One question to Mik: I know that the prospector has proven itself for a couple of centuries but would like your comments on the RedBird design also in the Canoecraft book.
Ta

Boatmik

2nd August 2006, 03:05 PM

Hi Guys
In fact I just purchased enough timber to do a caone for just under $130 whereas quality ply would be about $250 ...

One question to Mik: I know that the prospector has proven itself for a couple of centuries but would like your comments on the RedBird design also in the Canoecraft book.
Ta

It differs a lot if you can do your own timber milling - strip boats can be done quite cheaply. But for most they end up having to buy the premilled strips which makes the strip boat quite a bit more expensive.

These days you can often spend serious amounts of money on clear cedar if nothing falls in your lap (though paulownia would be my choice for my next stripper - unless I decided to go for Balsa again - there is something really nice about building in Balsa)

As far as the Redbird goes - what is there not to like about the Redbird! A truly striking boat that paddles really nicely.

A bit more speed (from the length and fineness) - a bit less carrying capacity (but plenty for a week away if you travel light).

The Redbird and Prospector are the best canoes in that book - in my opinion! And I give a few extra points to the Prospector because of its reputation and because, dammit, I have always been a sucker for straightforward looks and behaviour - workboats - you have to love them!!!

MIK

Wood Butcher

2nd August 2006, 03:12 PM

(I can't quite recall which participant here is directly involved in the Qld Assoc.)

onthebeachalone (http://woodworkforums.com/member.php?u=10711);)

Boatmik

2nd August 2006, 03:31 PM

As far as the Redbird goes -

A bit more speed (from the length and fineness)

Note though that the Prospector ain't a slouch either! And the Redbird's advantage will start dropping as you load it up.

MIK

Ramps

2nd August 2006, 03:33 PM

Ahhh very true Mik ...

I put it in the "longer to build" category rather than "increased cost" but that is again a personal choice.

And yes the timber I bought the other day is Paulownia. I was rather pleasantly surprised when I went to pick it up thinking it would look as boring as Balsa sorry Mik no ofense meant as your Wee Lassie does look wonderful and it was what sold me on Paulownia, thinking if you could make Balsa look great then I couldn't go worse with Paulownia. Looks a fair bit like Tassy Oak/Vic Ash if you ask me.

Another Q for you Mik and I'll keep it on this thread as I think it's as relevant to Clinton as it is for me.

Why do you say the RedBird has a lower carrying capacity than the prospector?

The Boat is 1.5 metric feet longer and has the same beam as the prospector. Admittedly it has a 12" depth rather than a 13 inch ... is that the main reason for the comment. The Redbird doesn't look as "duck like" (how's that for technical) as the prospector but I feel it's mainly due to the extra length.

Why I ask this is that I had pretty much decided to make the Redbird this weekend:D ... well at least cut the moulds but I can easily be swung towards the Prospector if there is good reason to do so... one would be carrying capacity ... another is I thought it would track better for a novice like me. The main reason I have chosen the RedBird though is "Gee that looks nice" but it was touch and go with the Prospecter when reading the descriptions.

I know it's not a matter of which is "best" but I would appreciate your opinion again on this.

I'm ambidextrous when it comes to beers and boats:)

Clinton1

2nd August 2006, 03:57 PM

Good questions Ramps, good on you.

My plans to build a kayak out of Nick Shades book has been waylaid due to the selfish, egocentricity of a single seated kayak

Thats what my wife said! Which is why the kayak is second on the list... :(

Wild Dingo

2nd August 2006, 08:27 PM

Ahem... scusey tha slight hyjack ;)

Hey Ramps!! Where did you get the Pauliwanna mate?

Boatmik

2nd August 2006, 08:38 PM

Why do you say the RedBird has a lower carrying capacity than the prospector?

I'm ambidextrous when it comes to beers and boats:)

Howdy Ramps,

The Prospector was a real prospector's boat originally - so will carry enough for a winter up the Yukon somewhere and then bring 1000lbs of pelts back down to Hudson Bay. (I don't promise that my geography is any good at all - but the names are so evocative I thought I would throw them in!)

If you are planning to head away for a month you would have to do some serious thinking with the Redbird to keep things simple and compact - but with the Prospector will carry a stupid amount of gear.

So for normal modern uses it probably doesn't matter. Weekends away - a week away - no difference.

And you are right about the tracking. Redbird is a bit more straightliney whereas the Prospector has a balance. Generally again in modern use terms - probably little difference.

Both great boats and your heart seems to be a bit more with the Redbird - and that's the main thing.

MIK

Ramps

2nd August 2006, 10:34 PM

Thanks Mik for putting my mind at ease

Yes I don't think I'll need a months worth of supplies and returning with supplies to last me another year. I prob do need the tracking though (as do the others sharing the canoe) as we are all raw amateurs.
Mostly it is likely to be used for day trips and perhaps an overnighter, if we get more serious than that I'll just have to jump into the kayak to leave room for the gear :D or build another smaller canoe (wee lassie II perhaps) for a couple of bods.

Dingo
the Paulownia was bought from Highpoint timber in Rockingham, apparently there has been a bit changing of hands and they don't stock the sheet material that they had but they still have all the solid paulownia. Mostly from china but some sourced locally and more coming on line soon as a paulownia investment company has bought them out. Still operating the same though.

Clinton sorry about the deviation but I hope it wasn't too wide and still relevant to your decisions

Wild Dingo

3rd August 2006, 02:42 AM

Cheers Ramps :cool:

Mik whats the diamensions of the Prospector? sounds like a ball tearer!

Maybe when were both done building we can do the "Im a lumbajack an I dont care" thing and load up and head up the mighty Collie river eh Ramps?... mmm that Collie river comment doesnt have the same ring as say the Yukon does does it? sigh :rolleyes: aahhh well no worries :cool:

Boatmik

3rd August 2006, 10:36 AM

Hi Dingo,

Ramps is the man to ask - I think he has the book.

But around 16ft x 34ins (I can even use traditional measurements!)

Actually still much more comfortable for talking about boats - I know EXACTLY what 100 square feet of sail means but have trouble wrapping my brain around 9.3sq metres!

Though Imperial are terrible to build with compared to metric. What is one third of 5ft 7 7/8 ins. It just makes me feel stressed!

But I think you (Dingo) would be a man for a Prospector - as I said - a real workboat! And it has that same sort of understated - fit in with the crowd type elegance of a Maine Lobster Boat or one of the smaller old Sydney Harbour Ferries or the commuting launches that used to cart the workers to the Garden Island and Cockatoo Island Naval Docks.

Until you look closely and start to see just what a sophisticated shape it is -
How they get those lovely ends to match in with that boxy midsection
How the boxy midsection doesn't look boxy
How the high topsides don't look high

http://www.bearmountainboats.com/gallery/Prospector/Prospector_08.jpg

(sorry I thought I was linking to a single photo)

For me it is up there with the Rosinante or Araminta or Oughtreds Whilly Boat (rerigged with a mizzen to look proper).

And just so people know what we have been talking about - here is Ramp's Redbird. Redbirds are really striking boats

http://www.bearmountainboats.com/gallery/Redbird/Redbird_03.jpg

To put it back into the thread - Clinton - before you saw the Wee Lassie being compared with a glass canoe. You can see that these two have the same features as the Lassie. The hollow ends (the fins at bow and stern formed by the shape of the stems) fading very nicely into the load carrying mid section. See how the Redbird's hollow is very long compared to the Prospector - also the fore and aft curvature (rocker) of the keel is very straight - though you can't see it here - giving even more directional stability than the Prospector.

As you look at more and more classic canoes you start to see just how WRONG most of the fibreglass boats are - mostly designed by people building fibreglass industrial tanks or swimming pools. Foisted on us by the same people who sell outboard tinnies with a set of oars!!!

You can look through more boat p*rn at http://www.bearmountainboats.com

MIK

Clinton1

3rd August 2006, 11:54 AM

Ramps,
No worries, keep it up.:)

Something I've learnt is that sometimes you don't know what you don't know. Confusing? So it is good to sit back and listen, from that I can find out the things I don't know about - and can then start fixing that.

For example: I would not have thought to ask about using Paulownia. Thanks for that one.

Also, your comments on the cost difference between your Paulownia strips versus ply were good.

Boatmik

3rd August 2006, 12:46 PM

And yes the timber I bought the other day is Paulownia.

I was rather pleasantly surprised when I went to pick it up thinking it would look as boring as Balsa sorry Mik no ofense meant as your Wee Lassie does look wonderful and it was what sold me on Paulownia, thinking if you could make Balsa look great then I couldn't go worse with Paulownia. Looks a fair bit like Tassy Oak/Vic Ash if you ask me.
Howdy Ramps,

I am keen to hear how the Paulownia goes. There is a bit on the net and other places suggesting that because of the lower strength compared to Cedar that the Paulownia strips need to be thicker.

Don't be swayed - use at the same thickness as cedar (6mm) and save a bit more weight. The balsa canoe with 6mm hull and much lighter glass than you will be using was plenty strong enough.

My take is that it is the timber that gives the boat its strength and the glass that stops the timber from denting.

This is a practical view only. The engineeering view (ie the correct one) is that the glass gives the timber cross grain strength (its real function) but the 0.75oz glass that I used proved adequate for that purpose.

So if a very light glass gives enough cross grain strength - if follows that heavier glass fulfills a different function - which is to protect the timber from denting in contact with stones or snags. Usually it is land based damage.

Back to Paulownia

Keep the gunwale trim keel and perhaps external stem in contrasting colour and it will be just gorgeous.

BTW the Balsa Canoe was even more gorgeous in the flesh than the photos show - I'll have nothing said against balsa from a decorative point of view!!! In a way I think the hull timber is irrelevant - it is the trim that gives you the shape of the boat so that should be really pretty (I found some Australian Red Cedar for my tiny gunwales and inwales.)

Yep - I thought the Balsa looked like Tassie Oak at the time too!!!

There are a couple of little tricks as far as setting of gunwales too which I might tell you later if you are interested - I'm off to the city.

MIK

;-)

MIK

Ramps

3rd August 2006, 05:47 PM

Yeah you’re right Mik I do have the book

For Dingo … as per the specs in the book … obviously the weights as what you make of them. At least it gives you a comparison between boats and like Mik said there are some other wonderful boats in there as well … these are two of the larger models

Redbird
Length: 17’ 7 ½”
Beam: 35”
Beam WL: 33 ½”
Depth: 12”
Draft: 4”
Weight: 50lbs

Prospector
Length: 16’ 1”
Beam: 35”
Beam WL: 33 ¼”
Depth: 13 ¼”
Draft: 4 ¾”
Weight: 50 to 60lbs

Mik I know it’s not too late to change but if we’d had this conversation a week or so ago I might well have decided on the Prospector … mainly because for the same sort of carrying capacity (a major decider) to have a canoe 1 1/2’ shorter to man handle on to the top of a car etc would be a considerable advantage.

Don’t get me wrong Mik, like I said the Balsa looks fantastic… different to WRC which I love but still fantastic. It is just that I love the look of WRC. I intend to put a couple of strips into the sides … in a similar location to the feature strips on the pic of the Redbird that you posted (thanks for that, nice pics). I am thinking a bit of Jarrah for Gunwale, trim and stem (outer) is that overboard (sorry no pun intended). Do I need the strength for the inner stems or will a bit more paulownia do? Would love Aust Red Cedar but it seems a little hard to get hold of at the moment.

One more question to do with construction … and I know the debates been on for years but … what would you recommend for a family based canoe, like this, for f’glass … 6 oz both inner and outer or 4 oz inner, 6 outer or an extra layer along the keel … I’ve heard all these (plus more) recommendations.

I see your point about the rising up at the bow & stern compared to the prospector … probably one of the features that attracted me … the more traditional look … silly to ignore the practicality of them becoming sails when you don’t want them to be.

In Nick Shades “The strip-built Sea kayak” there is a great analogy of the timber/glass construction with a metal I-beam and the wood is really only holding the two skins apart. In this analogy to “dent” (as distinct to puncturing) the canoe the inside glass would have to stretch and the outside layer would have to compress (this is where glass has it’s strength). Where the “strength” of the timber comes in … in my way of thinking … is it has to have a good compression strength ie how crushable is it. This is different from the tensile strength etc that is easier to come by. I can not find anywhere the compression strength of Paulownia so I’m just winging it but I would expect it to sit somewhere between Balsa and WRC … hmm might be worth some home testing … I’ll keep you posted … pun intended. Therefore if the timber crushes then the two layers of glass are sitting side by side and can therefore be “folded” quite easily. (see attachment)

I promise I’ll post my own thread up after the w/e when I’ve got something to show for it then I can ask all my questions and keep all the answers together for others to refer to … could be another Eureka thread coming on here. I’ll ask about the gunwales there and at a later date … thanks for the offer Mik.

Thanks for putting up with me Clinton

Boatmik

4th August 2006, 04:00 PM

Mik I know it’s not too late to change but if we’d had this conversation a week or so ago I might well have decided on the Prospector … mainly because for the same sort of carrying capacity (a major decider) to have a canoe 1 1/2’ shorter to man handle on to the top of a car etc would be a considerable advantage.

Go with the Redbird because you like its looks! Either canoe would be fine for you - so go for the one that you are just most drawn to.

An important note - spend a lot of time with a torture board getting the outside of the hull fair. This is the bit where people often skimp because they don't understand fairing. The general rule isOnce you have faired the outside of the boat with a torture board around 500 to 750mm long then the undulations are over 500 to 750 mm intervals.

If you then go back to a random orbit sander and get stuck into the surface then the undulations are now worse - the 150mm of the disk is the spacing for the undulations.

I am thinking a bit of Jarrah for Gunwale, trim and stem (outer) is that overboard (sorry no pun intended). Do I need the strength for the inner stems or will a bit more paulownia do? Would love Aust Red Cedar but it seems a little hard to get hold of at the moment.

Jarrah is the right colour but is WAY too heavy for a boat of this style. The boats breathe lightness. Would be a pity to bog it down. Because the boat is so light you don't need the strength and toughness of the Jarrah anywhere really. If hit the boat is light enough to move out of the way to some extent.

Jarrah would be for the keel though - but keep the dimensions down to the minimum suggested in Canoecraft (or less) Have a look at the Balsa Canoe page to see how little you can get away with. Though gunwales and inwales I would stick to Canoecraft's suggestions or a little less.

What I sometimes do when I want to keep bits of the boat light is to use the lightest wood I can find for bits that are going to take some abrasion (eg external keels, skegs, bottom runners) but cap them with a 6mm strip of something like Jarrah. Not much extra weight but you get the full benefit of the tougher wood. When it becomes too damaged plane it off and put a new Jarrah strip along the edge.

One more question to do with construction … and I know the debates been on for years but … what would you recommend for a family based canoe, like this, for f’glass … 6 oz both inner and outer or 4 oz inner, 6 outer or an extra layer along the keel … I’ve heard all these (plus more) recommendations.

I generally use 6oz because it is readily available. But would have no worries about using 4. Or would have no worries about using 0.75 (though it would need to be doubled in the bottom of the cockpit and the areas of the bottom on the outside that might contact the ground.

My feeling is that most recommendations simply express personal biases rather than any sort of firm fact - generally if a single facet answer is being offered it is opinion.

6oz will resist denting quite well, 4oz will still be fine. 1.75 you have to start putting the boat down on the ground upside down so that stones don't dent the bottom - though Paulownia would be much more resistant than balsa!!!

I see your point about the rising up at the bow & stern compared to the prospector … probably one of the features that attracted me … the more traditional look … silly to ignore the practicality of them becoming sails when you don’t want them to be.

With a proper classic canoe shape you can go quite hight and it still works OK because the ends of the boat have enough grip on the water to resist the sailing effect.

In Nick Shades “The strip-built Sea kayak” there is a great analogy of the timber/glass construction with a metal I-beam and the wood is really only holding the two skins apart. In this analogy to “dent” (as distinct to puncturing) the canoe the inside glass would have to stretch and the outside layer would have to compress (this is where glass has it’s strength).

Denting is very localised on the outside skin of the boat. Like bruising a peach by squeezing it with fingertips. The bending loads are insignificant (the I beam analogy) - but the cross grain compression loads where the stone is pressing on the hull are very high

Where the “strength” of the timber comes in … in my way of thinking … is it has to have a good compression strength ie how crushable is it. This is different from the tensile strength etc that is easier to come by. I can not find anywhere the compression strength of Paulownia so I’m just winging it but I would expect it to sit somewhere between Balsa and WRC

Exactly right - and if my balsa canoe can handle all sorts of nasties then the Paulownia will be fine. Strengths of timbers are quite proportional to their densities as you suggest. There are some exceptions but not by a huge amount

Therefore if the timber crushes then the two layers of glass are sitting side by side and can therefore be “folded” quite easily. (see attachment)

Sea kayaks are quite different creatures from canoes - I have a word for you ... it is ... surf landings.

The sort of damage that Nick is talking about is from wrapping a fully laden seakayak against a rock when surfing in. I have never seen damage of this type. In fact I haven't ever seen damage that has gone through to the inside skin. Most of the denting that I have seen has even been without cracking the epoxy. Just like denting a peach skin.

Thanks for putting up with me Clinton

Me too Clinton, though hopefully some of this discussion is useful for you too?

MIK

jackbat

4th August 2006, 04:11 PM

Clinton
I can see it has been a while since you posted this thread and normally I wouldn't get too involved but I read some pretty crazy (yet entertaining) materials in the responses.
I have been doing this for over 20 years and here is my two cents worth.

First off the inner/outer stem.
Any canoe can be built with one piece stems if you want. The invention of the two piece stem was a happy by product of concoctions like epoxy that allowed you to break the stem in two and still end up with a strong member. In fact it is a better structural member than the one piece stem. The older canoe designs used what was called Sawn or Hackmatack stems. Hackmatack were pieces of natrually curved limbs that would take the shape of your stem with a little trimming. Sawn stems still are in play today but they are first put together with a number of pieces joined with a stem knee.

The question is why would you want to rabbett out a stem? If it is for authenticity then fine, if not then you should really consider a two piece stem. Especially for a canoe as you can steam them with a tea kettle and a cheap pvc pipe.

Not sure I understand the first mold board question. There are two types of forms on a canoe. A body form and a stem form. The stem form is mounted at a 90 degree angle to the body form and used to mount the inner stem on (or full stem if you are using one).

You seem to be refering to a bulkhead. Typically on a boat with a bulkhead such as the bay hawk wood strip boat in this picture

http://www.sandypointboatworks.com/images/Bay_hawk_transparent.jpg

have bulkheads that are made using one of the body molds as a pattern.

Designers do in fact use composite materials for the lamination of the stems. When you take three 1/4" strips and laminate them together around the stem, the end result is stronger than anything else I know of. In fact I had to prove to someone just recently that the wood would break long before the lamination would. Believe it, it is a fact. I have done this on dozens of boats.

You asked about strip canoe designs versus plywood being interchangable. That depends on what kind of design you are talking about. Plywood planked, or lapstrake. It will make a difference. You can strip build a plywood design but you can not always (in fact almost never) plywood plank a wood strip design.

If the design of the canoe is done well then not only is there no reason to put a keel on a canoe but it is typically detrimental to the design. Different canoes are designed to handle differntly on different waters.

Fist off, unless you plan on putting enough keel on a canoe to ballast the water to keep you from tipping then it is a waste of time. With a 200 lb person in a small canoe I figure the keel would have to be about 2 to 3 feet deep. Keels in a canoe would only serve to make the canoe track straighter.

Let me reiterate that if the canoe plan is designed well and for flat waters then it should track fine without one. Normally the only time you see a keel line on a canoe is with the cheap plastic ones you buy from the store.

Well, take it for what it is worth, but that is my story and I am sticking with it.

If you want to see more pictures of the process you can find them here.

WWW.sandypointboatworks.com (http://www.sandypointboatworks.com)

Feel free to send me an email if you have any questions.

Good luck,
Jack

Ramps

4th August 2006, 04:38 PM

Thanks Mik

I can go ahead and order some pox & glass now

The contrasting timber could be an intereting challenge ... still can be looking while stripping and might well just put the one 6mm strip of Jarrah on the outside of the outside stem ... have to do more investigations as to what's available for the trims and gunwales though. Anyone in Perth have any ideas on what might be both suitable and (the biggie) available? Might be someone at the ww show w/e after next?

Clinton1

4th August 2006, 08:33 PM

Ramps and Michael,
Frankly, you guys can bounce questions and answers as much as you like - believe me I am finding it very informative.
You are raising issues that I would not know to ask about.... I've been off to look at the Redbird and Bear Mountain sites, a Canadian wood canoe forum and searched Wik for a few terms. Its all good, and I've been content to 'sit back, listen and learn'.
I have not been able to speak with, and listen to, someone that has made a stripper, or a boat designer - until now! BM and WD contributed a lot, so are you guys.
Thanks, can you stop worrying that you are "wrecking my thread"? KEEP GOING! :)

Clinton1

4th August 2006, 08:53 PM

Jack,
My initial questions are based in my complete lack of knowledge. That has changed just a tiny bit, but I'm still happy to call myself ignorant!

My 1st stem question was mostly based on an inability to understand the function of having 2 stems, i.e. wouldn't one be sufficient, why the need for an outer? I was imagining the work to shape the inner, fair and match the strips, then form the outer. I was thinking that 1 inner, fair and match the strips, then glass and epoxy and add a brass rub strip seemed 'easier'. This led me to think of doing a rebate on the inner. i was thinking of the economy of effort - basically looking for a lazy way.

The mould board question: I was thinking "why not put the 1st mould board up very close to the 1st stem. Do away with an inner stem (& outer), use an 'outer moulding pattern' and fill the area between the mould board and 'outer moulding pattern' to hold a expoxy and reinforcing cloth (what I call a 'composite material') to create a solid piece that acts as inner and outer stem. When the composite sets, remove the 'outer moulding pattern'. Basically 'cast' a piece of solid plastic. It was mentioned that there would be a trade off for weight, and that perhaps I shouldn't experiment on a first build, rather stick to a tried and true design and get some experience first.

An example of what I call a 'composite material' is the process of using layers of veneer/cloth/carbon fibre/canvas with a good epoxy that affords some small amount of flexibility. Veer, epoxy, veneer, epoxy and continue putting down layers, then clamp and let set.
If you do this with plane shavings, and use the right amount of epoxy, you get a really stable material that almost looks like wood, with the strength of epoxy. I learnt about this from Bridge City Tool Works "Juara" wood. Basically it takes advantage of the superior strength of epoxy, with the grain of wood. This ties in well with your comment on laminations - think of it as lots of really thin laminations.
Cameron Potter on this site does the same thing, but uses cloth instead of veneer/shavings - and turns stunning, strong, lathe tool abusing, pens out of it. The first denim/epoxy block I made has been sanded, drilled, sawn, filed, rasped and had threads tapped in it and bolts fitted. Tough stuff.

I've got an inquisitive mind.:rolleyes:

Keel: I accept that it is a bad idea, and that the form/design of the front and rear (prow and bow?) actually achieves what I was thinking of.

The "Adirondack Guide Boat" on your website looks good. In the top piccy it seems to be hardly sitting in the water. I guess it can carry a fair load?
Are there any other pics that you can post into this thread? I could not enlarge any of the pics on the website. Its a bit big for me, but looks good!

Thanks for your input - it is much appreciated.

jackbat

5th August 2006, 04:48 AM

Clinton,
In fact you don't need an inner or outer stem at all for a wood strip canoe. If you pick up a copy of Gil Gilpatricks book you will see that he built boats without using stem pieces at all.
He simply shaped the stem form and worked the strips together at the ends. Then he sanded, faired and glassed them. There are a number of people who build like this. For me I don't see the bennifit to doing this. You have to spend a lot more time fitting the strips and in general they do not come out looking as good.
Where the inner stem is actually a structural member of the boat that helps to hold the boat together and gives a good landing for the strips, the outer stem of the boat serves no purpose other than to protect the stem and to add a bit of class. Before you attach an outer stem piece, you glass over the stems. You could simply double up on the glass and eliminate the outer stem piece if you wanted, but I don't think the boat would look finished.
Experimenting is good, I do it all the time, but be carful how you use epoxy on a real project as it has very different properties than poly resin. Epoxy is very brittle by its nature. When used in conjustion with glass it gains a bit of flexibility becasue the glass holds it together but by itself it will crack fairly easily under flex stress. Tony Delima , the inventor of MAS Epoxy is a friend of mine. If you ever have questions about epoxy and you want an answer that you know is right he is always willing to talk to you. You can find his number on his web site Masepoxies.com Great guy and way smart.
Laminating the stems is as simple as can be if you have a tea kettle. In fact the first time I did it was in my bath tub with hot water 25 years ago. Worked well but took days for the wood to dry enough to actually laminate.
I love the Adirondack guide boat. It has been a favorite of mine for 20 years. It just took until now for me to get around to making up a set of plans for it. The boat is decieving from the above water view. I posted a pic on the web site so that you could see the lines below the water.
http://www.sandypointboatworks.com/images/forms_view_for_plans.jpg

The boat is about the same size as a canoe. It is only 16 foot but the beam is about 10 inches wider than a typical canoe. I have another boat plan and video which is built similarly but is smaller and lighter, it is called the little rob. A very traditional Rob Roy style canoe. You sit on the bottom and paddle like a kayak. This is the go to boat for me becasue it only weighs about 30 LBs and I can throw it in the truck and be on the water in minutes.
http://www.sandypointboatworks.com/sitebuilder/images/little_rob_42-250x165.jpg

If you want to see some building pictures, including the stem lamination you can find them here at http://www.sandypointboatworks.com/Picsfromtheshop2.html
I have a couple dozen pictures of the Adirondack Guide Boat if you are interested becasue a customer just sent me a bunch from one he built. Give me an idea of what you would like to see and I am happy to post them.

jack

Clinton1

5th August 2006, 04:17 PM

Jack,
Any pics are good - how about you put up whatever you think you can use to educate me? Mik said that "Eyes are really important in understanding boats", I guess that I'm asking if you can use a pic to tell me how the boat lines make it "fast straight and stable". If you could do that it would help me.

Also, what was the use that the boat was designed for? Was it a day tripper for getting up and down a waterway, for extended trips, a workboat? What sort of weight does it carry?

You are in North America - the Ma in your contact address is Massachusetts?
I'm a bit envious of you guys and your access to the waterways and rivers that are in North America. 80% of Australia is desert, and the only river that I've seen that compares to anything you have is the Ord River in Western Australia. I haven't seen them all, but most of our rivers are muddy and short. :(

Thanks,

Boatmik

5th August 2006, 08:06 PM

Howdy Clinton,

Straight

The tendancy for the boat to go straight comes from three places

One is the same as the Classic canoes. Have a look at the Body Plan - the line drawing in Jackbat's post immediately above. Note how the sections are convex curves (looking from the outside of the boat!) but down near the bottom they become concave. This has the same effect as the keel.

The other reason is because the width of the boat at the waterline is quite narrow - even though the boat is quite wide above the water. Something long and thin is much harder to turn than something short and fat.

Note how there is not much difference in depth between the bottoms of each section - this shows the bottom doesn't curve up much. This is called rocker. This boat and Redbird canoe have relatively rocker so are good straight line machines, the Prospector has a bit more rocker so has a balance between turning and going straight.

Fast

Narrow usually means fast - this boat is narrow at the waterline.

Also the low rocker makes the boat faster.

The reason for both is that the water is pushed down and out the minimum amount so the water can move through. Saves energy.

Stable

The guideboat is quite narrow on the waterline so it might have a feeling of being a little bit unstable at small angles of heel. But it is much wider than a canoe at deck level - so as it heels a bit more the stability will pick up very quickly.

The beam affects the stability of a boat proportional to the cube.

So if a boat is twice as wide then the stability goes up 2 cubed ie 8 times.

In this case the beam of the Guideboat is around 4ft (from memory - Jackbat - correction?) so it has about 33% more beam than the canoes that we have been talking about. So cube that to get the change in stability - 1.33 cubed = 2.35. So the guideboat has *around* 2.3 times the stability.

the *around* is because this proportional rule depends on the hulshapes being identical apart from beam - but the guideboat shape is different of course - so the analysis is only approximate.

Hope I have explained the jargon well enough.

MIK

Wild Dingo

6th August 2006, 02:07 AM

You are in North America - the Ma in your contact address is Massachusetts?
I'm a bit envious of you guys and your access to the waterways and rivers that are in North America. 80% of Australia is desert, and the only river that I've seen that compares to anything you have is the Ord River in Western Australia. I haven't seen them all, but most of our rivers are muddy and short. :(

Thanks,

Dont be envious Clinton... get the hell out and have a look around!! MAN Aussie has some of the best waterways in the world excluding NONE! :cool:

The Ords good for sure but then the Swans excellent as well long and with everything from fast water (Avon Decent anyone?) to slow shallow water to deep water... Canning River, Murray River, (to name but a few) Estuarys: Lauschinalt and Mandurah (and others) along with many Lakes Dams and offshutes... muddy shallow? Not to many that Ive seen over here... theres all the waterways you could ever want over east... some shallow and muddy most not... how fars the Murrumbridgy go? The big Murray River how fars that? in all their lengths there must be some good waters... Im unfamiliar with Queenslands rivers and such but Im bloody sure theres some brilliant places on them!! gotta get out and on the water to find them maybe but theyre there mate

As for much of Aussie being dry well the Gascoyne River is dry for 7 years generally then they have a cyclone and it floods for weeks after its bloody fantastic!... If your game and stick to some basic guidelines the Mary River is an awesome sight to paddle as is the Kathrine River... basic guidelines? Such things as being aware that Crocs live there and Crocs just plain dont care about you one iota other than as tucker is the best bit of guideline advice anyone can give or get up there but still if you game (Barramundi anyone!!) and careful its bloody brilliant!!

I think such things as the intercontinental waterway is something we here in Aussie should hound our polititians for... imagine a canal large enough for a couple of sailboats or powerboats to pass each other without disturbing their wakes going right around Aussie?!! MAN!!! :cool: HECK even one straight across the damned Nallabor would be most excellent!! Id rather take several weeks transversing Aussie in a boat than in a ruddy car ;)

To my mind there is NOTHING to be envious about the US waterways over our own!

Boatmik

6th August 2006, 02:09 PM

I think such things as the intercontinental waterway is something we here in Aussie should hound our polititians for... imagine a canal large enough for a couple of sailboats or powerboats to pass each other without disturbing their wakes going right around Aussie?!! MAN!!! :cool: HECK

That means I could take my canoe down to somewhere near Deepdugs house drop it in, head left and hit Midges house in about 6 months.

Howdy - just dropping in for a quck cuppa.

MIK

Clinton1

6th August 2006, 03:24 PM

I like my rivers clear.
Only seen it three times, the Snowy up in the Snowy's foothills (dodge the rocks due to the level tho), the NQ rivers in the wet season (they flow a bit fast then!) and the Ord above the dam.
Every other river has just been thin mud!

I'm yet to go to the southern part of WA, and Tassy.

The Ord is bloody fantastic, under rated, remote, hot, humid - which is good cause it keeps the population down. :rolleyes:
North America seems to have a lot of wild rivers that flow clean and clear... benefits of two big mountain ranges running either side of the country I guess.

KJL38

6th August 2006, 10:46 PM

Hi, I'm new here, hope you can help me out. Could anyone give me their opinion on whether paulownia would be strong enough for a sea kayak used in the surf? When I get round to it I intend building a low volume day kayak, possibly a Black Pearl. http://www.thomassondesign.com/edoc/eblackpearl.php

Clinton, not sure if you're aware of these sites but there's some good info on sailing canoes at http://dragonflycanoe.com/ and http://freepages.genealogy.rootsweb.com/~fassitt/canoe_mirror/canoe_sailing.html

If you are looking for clear, large volume rivers to paddle on there are quite a few in New Zealand.

Kelvin

Clinton1

7th August 2006, 03:33 PM

G'day Kevin, welcome to the forum.

I'm sure the guys will have an answer for you shortly.
I'll have to check out those links - thanks!

bitingmidge

7th August 2006, 03:43 PM

Hi Kelvin,

Paulownia won't be a problem, but depending on what you mean by "used in the surf" the black pearl could be!

If you are paddling out to go for a bit of an open sea jaunt, no problems, although you'd need to take a bit of care coming in.

Those loooong skinny bows may be great for paddling through waves, but you don't want them to dig in be coming down the face of a short wave!

For surfing, usually kayaks are quite short, with a relatively flat bottom and hardish chines that can be used to dig into the side of the wave for tracking on the way in. Or has all that changed in the last few years?

Cheers,

P

KJL38

7th August 2006, 05:26 PM

"Used in the surf" includes both the getting in and out and surfing. I have short kayaks for whitewater/surf but a lot of guys take there seakayaks surfing as well. I currently have an NDK Explorer sea kayak which I've only pitchpoled once :) but would like something lighter and sportier for day paddles and playing. Glad you think paulownia will be up to it, now I just need to get organised enough to build my new shed so I can start working on a kayak. Any suggestions on thickness for the wood and what weight of glass would be best?

thanks
Kelvin

Boatmik

8th August 2006, 02:50 AM

Hi Kelvin,

For a surf landing that goes OK there is no difference in timbers of course!

But if something goes wrong and you wrap the boat around a rock there will probably be little difference between timbers - if it is hard enough to damage one of them it will be hard and heavy enough to do significant damage to all.

I haven't got enough time at the moment to dig out an old spreadsheet I wrote as part of my engineering course to get a quantitative answer about strength and impact absorbtion, but I can suggest a ballpark solution.

Normally strip boats use 6mm Cedar. If you go to 7mm Paulownia the strips will have pretty much the same impact absorbtion and tensile strength.

But because of the added thickness the glass will be more effective in stiffening the skin.

And because Paulownia is lighter than WRC you won't have added any weight.

I don't know what the sea kayaking hotshots are using for glass. For normal use 6oz (200gsm) is fine, but there might be some info about boats that are going to be surf landed on some specialist sites on the net.

Or in the plans!? The info should be there.
______________________________

Just did a fair bit of fishing through Nick Schade's site. It looks like the general run of kayaks are glassed with either 6oz or 4oz.

If you are likely to be wrapping it around rocks I would take the heavier!

MIK

MIK